Humayun Nama is a book that was written by Gulbadan Begum. Gulbadan Begum was the daughter of Emperor Babur and elder sister of the Mughal Emperor Humayun. She wrote the book during the reign of her nephew, Emperor Akbar, and it is considered one of the earliest and most significant historical accounts of the Mughal Empire.

Option 1: Humayun - This option is incorrect because Humayun was the Mughal Emperor and not the author of the book.

Option 2: Mirza Kamran - This option is incorrect because Mirza Kamran was Humayun`s younger half-brother and not the author of the book.

Option 3: Bairam Khan - This option is incorrect because Bairam Khan was a noble and military commander during the reign of Emperor Akbar and not the author of the book.

Therefore, the correct answer is option 4 - Gulbadan Begum.